Emagram

An emagram is one of four thermodynamic diagrams used to display temperature lapse rate and moisture content profiles in the atmosphere. The emagram has axes of temperature (T) and pressure (p). In the emagram, the dry adiabats make an angle of about 45 degrees with the isobars, isotherms are vertical and isopleths of saturation mixing ratio are almost straight and vertical. Usually, temperature and dew point data from radiosondes are plotted on these diagrams to allow calculations of convective stability or Convective Available Potential Energy. Wind barbs are often plotted at the side of a tephigram to indicate the winds at different heights.

First devised in 1884 by Heinrich Hertz, the emagram is used primarily in European countries. Other countries use similar thermodynamic diagrams for the same purpose. However, the details of their construction vary.

example:

See also

• Thermodynamic diagrams
• Skew-T log-P diagram
• Tephigram
• Stüve diagram

References

Thermodynamic Diagrams

Bibliography

• M K Yau and R.R. Rogers, Short Course in Cloud Physics, Third Edition, published by Butterworth-Heinemann, January 1, 1989, 304 pages. EAN 9780750632157 ISBN 0-7506-3215-1
• J.V. Iribarne and W.L. Godson, Atmospheric Thermodynamics, 2nd Edition, published by D. Reidel Publishing Company, Dordrecht, Holland, 1981, 278 pages, ISBN 90-277-1297-2, ISBN 978-90-277-1297-4